The 2006 BMW M6 also includes an M Variable Differential Lock, a mechanical limited-slip differential that helps regulate power delivery in slippery or split-surface traction conditions. The M Variable Differential Lock senses wheel speed, not torque, and when a speed difference develops between the two rear wheels, a multi-disc clutch delivers more power to the wheel with grip and less to the one that is spinning faster to maintain optimum traction. Of course, in the unlikely event that you do get the 2006 BMW M6 to overpower its huge tires and M Variable Differential Lock, there’s a standard Dynamic Stability Control (DSC) system calibrated specifically for M duty so as not to unduly interfere with having a good time behind the wheel. Equipped with a selectable M Dynamic Mode, the DSC can be programmed to allow additional wheelspin and oversteer for a wider performance envelope, and it can be completely deactivated if the driver wishes.